Open the PDF in a PDF reader that supports digital signatures
Locate the signature field or signature panel
Check whether the signature shows as valid
Verify that the certificate chain is trusted
Confirm the certificate is not expired
Confirm the certificate was not revoked
Check that the document has not been modified after signing
Compare the signer’s identity with the certificate details
Review the signature timestamp, if present
Use the PDF reader’s signature validation or properties panel
If needed, validate the signature with a trusted certificate authority or verification tool